Chicago Teachers Union President Karen Lewis today acknowledged that the issue of impending school closings, coupled with the rapid opening of taxpayer-supported private schools known as "charters," are affecting negotiations, particularly the issue of recalling teachers who are laid off when schools are closed.

"That's why we have such an issue on recalls," Lewis said. "We understand that whole movement of closing schools and doing it aggressively."

Union officials have complained that the administration is considering closing up to 120 public schools, prompting their demand that the district rehire laid-off teachers for job openings.

The mayor was repeatedly asked whether he plans to close schools next year and if so, how many. Emanuel didn't dispute that more underperforming and sparsely-attended schools will be shut down, but he wouldn't say how many.

"Nobody knows yet, because we haven't worked through it," Emanuel said.

Emanuel also said today that children should go back to school while negotiators stay at the table and craft a new contract for teachers.

"There's nothing that can't be worked out while kids stay in the classroom," Emanuel said at a news conference. "None of the issues are such that you can't do both simultaneously."

Emanuel already tried that approach on Sunday. He asked the Chicago Teachers Union to postpone a strike while it continued to work out deal with the school board. The union rejected it. The walkout is now in its third day.

Among the most contentious issues being negotiated are a new evaluation system and principals' ability to hire who they want.